Answers

Start by deciding if you'd like to have an above ground pool or below ground pool. There's gotta be a significant cost factor there I'd think.

You should decide if you want above ground or in-ground.  If you decide to go with in-ground, you should do some research on vinyl liner compared with concrete.  :-)  Good Luck!

Start by doing some research for your local area.

What type of pools work best for your ground condition; Gunite, Fiberglass, Vinyl Liner, Above Ground, etc?

If it is gunite, what style do you want; Freeform, Geometric, Lagoon, Modern?

Do you want a spa?  Do you want a waterfall?  Do you want to heat your pool?

What materials catch your eye?

Create a portfolio of pictures of pools that you like, this will help the designer really understand waht you are looking for.

Check out the companies that you call.

How long have then been in business?

Are they members of BBB?  Rating?

Do they have an office or do they work out of their house/truck?

DO they have insurance?!?